I got the MTA Postfix installed via apt-get and it for some reason it would hang upon start on postqueue -p. The "Gotcha!" was that Debian, for some reason I don't know, requires a file called /etc/mailname for postfix to properly start up.

Try this :

% hostname -f >> /etc/mailname

Then issue a /etc/init.d/postfix stop && /etc/init.d/postfix start

Voila! Go configure postfix and get your MTA running.